This proposal is in response to RFA-AA-12-008, Evaluation of NIAAA's Alcohol Screening Guide for Children and Adolescents. Of particular interest to the agency are evaluation of the Screener in clinical and/or other settings to predict alcohol-related consequences including use disorder; its use as an initial screen for drug use, cigarette smoking, conduct disorder, and unprotected sex; and its performance in making predictions concurrently and prospectively. This proposal targets these areas of interest. In addition, we will study implementation of the Brief Intervention (BI) associated with the Screener. There is a great need for both screening and BI in juvenile probation settings as many of these youths have great need but are underserved. Many probation departments are turning to BI to work with probationers and parolees. Screening and BI has demonstrated efficacy in these settings, and yet no randomized control trials have been conducted to evaluate effectiveness in juvenile probation settings. The long-term objective of this research is to enhance detection and service delivery to underserved youth. Probation Officers (POs; n=40) are randomized to Screener (S), Screener+BI (SBI), or coaching (CSBI). Youths (N=1000) are randomized to 1 of these 3 conditions, and all receive usual services (US). US consist of regular check-in with PO and access to referral services as needed (counseling, academic tutoring, etc.). Research staffers conduct in-depth assessment at baseline, 6- and 12- months. Sensitivity, specificity, and positive and negative predictive powers (SN, SP, PP, NP) are calculated to predict alcohol risk and consequences, as well as other risky behaviors concurrently and prospectively across age-groups. A 1-way design (S vs SBI vs CSBI) will be used to determine whether SBI and CSBI enhance youth services-use and reduce risks (e.g., alcohol use, risky sex). We examine moderators of outcomes (youth age, PO characteristics) and whether coaching (an important consideration in implementation science) in use of BI improves outcomes. This study will be the first randomized controlled trial evaluating the effectiveness of SBI in a juvenile probation setting. This study has significance in that juvenile probationers are at high risk for alcohol use and other problem behaviors; the justice setting offers a key opportunity to identify and access services for youths who are often otherwise undetected and underserved. Importantly, this trial would be the first in this setting to evaluate both the 2-question Screener and use of BI as presented in NIAAA's Practice Guide. It is crucial to evaluate the Guide in a variety of settings where youth at risk for alcohol problems may benefit from it.